With technical progress, economic development and globalisation, the volume of goods and services exchanged between countries and continents has been significantly rising since the late 20th century: In 1950, the global trade value of goods exported throughout the world amounted to approximately 62 billion U.S. dollars, while this figure stands at around 25 trillion U.S. dollars in 2022 [1].This increase in the volume of goods and services exchanged is especially noticeable for energy transport and trade (electricity, oil, gas) as well as data exchange (worldwide web, telephone, digital data). This called for more efficient and bulkier techniques to transport growing volumes, leading to an increasing number of underwater cables and pipelines, now totaling an estimated 485 underwater cables [2] and almost 1,900 gas pipelines in 2023 [3].
In the meantime, fishing activity has also greatly evolved, with the global fishing fleet doubling between 1950 and 2015 [4] notably driven by substantial expansion of the motorised fleet. Even if the fishing sector has been in decline for the past 20 years (read below), the expansion of the activity during the past century combined with the increased number of cables and pipelines have led to a rise in the number of challenging interactions between those two elements, with fishing vessels accidentally damaging cables with their gear.
This fiche sets out the range of interactions to be considered between the fishing sector and cables & pipelines, and what MSP can do to avoid and mitigate possible negative interactions.
Cables and pipelines
Across all sea basins, countries are connected by numerous submarine cables such as telecommunication cables that carry digital data, electrical cables that carry energy, and pipelines that transport oil or gas.
Most cables are buried beneath the seabed or are protected externally. However, some cables remain partially or totally unburied and lie on the surface of the sea floor. Pipelines are fixed and laid in protected trenches.
Cables and pipelines are strategic elements for the functioning of the globalized economy as they connect countries and continents and transport key flows. Disruption of their functioning could result in severe financial damage and impact key sectors. For pipelines the effects can be even more serious, as damage to pipelines can also cause serious environmental impacts.
Pipelines are mainly owned by private oil and gas companies, while telecom cables are owned by public limited companies and electricity cables by Transmission System Operators (TSOs). International key players are The European Subsea Cables Association [5] and the International Cable Protection Committee (ICPC)[6].
Fisheries
Fishing has a long history in all European sea basins, and is of particular importance to coastal communities, both economically, socially, and as a food source.
Capture fisheries have direct and indirect impacts on the marine environment and ecosystems notably through removal of biomass. However, thanks to innovations and regulations put in place over the last few decades within the EU, the state of fish stocks is progressively recovering [7], and conservation measures are expected to result in stock rebuilding.
The sector is regulated by the Common fisheries policy (CFP) [8], that aims at sustainably managing European fishing fleets and conserving fish stocks. Additionally, the Marine Action Plan aims at keeping fish stocks to sustainable levels and reducing the overall impact of fishing [9].
The sector is still facing major challenges and it has been in constant decline in volume for more than 20 years. This is largely due to the sensitivity of the business to the cost of fuel oil, reinforcing the need to decarbonise the sector as quickly as possible.
For more European statistics and data you can also visit the Eurostat website
Related challenges
The interactions between fisheries and underwater cables and pipelines can occur at different phases of the cable assessment and construction process.
Occupation of fishing zones during the assessment and construction stage: TSO's and cable owners must undertake an assessment phase of the technical options and constraints prior to the installation. Studies often require that fishing boats are not present in the area in order to ensure safety and not to disrupt the ongoing studies [10]. The same issue applies in the construction phase, when cables are being installed, the worksite needing to be empty from other activities due to navigational safety.
Operating phase: it is estimated that underwater cables are damaged by fishing gear or anchors about 100-150 times a year globally, and that more than two-thirds of all submarine cable faults are caused by fishing gear and anchors [11]. They represent the principal challenges in the interaction between underwater cables and fishing activity.
- Fishing vessels hooking a cable
A significant portion of commercial fishing activity relies on trawling, that involves towing a fishing net (“trawl”) behind a boat. Trawlers can drag their trawls within the water column (pelagic trawling) or over the seabed (bottom trawling). In the latter case, damage to cables or pipelines can occur from pulling fishing gear over them, or from fishing gear getting stuck underneath. This can cause cables or pipelines to be moved or dragged along, in the worst case leading to breakages.
- Anchors being dropped on the cable
Anchors being dropped directly onto a cable or pipeline can also cause localized damage. The anchors of commercial vessels can penetrate the seabed to a depth of almost one meter [12], and can therefore hook a cable, even if it's silted in. Further damage can occur if the anchor is moved and hooks the cable or pipeline [13]. This issue is not specific to fishing vessels but for vessels generally.
- Dangers for the vessel and crew
Snagging a cable can be extremely dangerous for the vessel and crew. Modern underwater cables carry high voltages: more than 10,000 volts for communication cables and 500,000 volts for power cables. Both can cause electrocution and be lethal. Moreover, when the cable is being lifted (intentionally or not) by the vessel, cable entanglement may affect stability and result in vessels capsizing.
- Dangers for the environment
In the event that a pipeline is damaged by an anchor or fishing gear, this can lead to leaking, potentially harmful elements into the ocean. Such spills can occur over a relatively large period of time as the leak can sometimes only be detected several weeks or even months after being hit by an anchor [14].
Related enablers
- Spatial restrictions to fisheries: Develop no trawl zones and no-anchor zones alongside cables and pipelines routes
A spatial option is to plan for no trawling and anchoring zones in specific areas. As discussed above, both represent a major cause of damage to cables and pipelines. Under Danish legislation for example, all cables and pipelines are protected by a 200m safety zone on each side of a subsea cable [15]. Anchoring, trawling and extraction among other activities are restricted within this area. The European Subsea Cable Association recommends observing a 0.25 Nautical Mile no-fishing zone (approximately 460 meters) on either side of cables [16]. However, this isn’t a legal requirement and cannot be enforced. As for pipelines, the Petroleum Act (1987) prohibits fishing from taking place within a safety zone of 500 meters around surface platforms and some subsea infrastructure [17].
- Map out existing cable routes
Such maps or charts can enable fishermen to know the locations of cables and avoid possible accidents before they happen. As an example, on a global scale, the company TeleGeography developed an interactive submarine cable map showing the majority of active and planned international submarine telecommunication cables worldwide [18]. Similarly, the ICPC developed a list of submarine power cables. Such maps can also be developed at basin scale, as exemplified by the Baltic Sea map [19] or the North Sea map [20] developed by the Federal Maritime and Hydrographic Agency in Germany. The KIS-ORCA European project also aims at providing a map showing the complete coverage of offshore subsea cables and renewable developments [21]. It is essential that information on cable locations is correctly disseminated quickly to avoid accidents. In the Netherlands, it is recommended by the central government that new cables are included in shipping charts as quickly as possible so that sea users and notably fishers know where they are located and avoid accidents [22]. Moreover, in the UK, such maps must carry an appropriate legend explaining if the pipelines carry water, gas or oil, and be accompanied by a suitable cautionary note the case of oil or gas pipelines [23].
- Use MSP to encourage stakeholder dialogue and co-design suitable cable and pipeline routes
Involving stakeholders of the fishing and cable sectors within the MSP process to co-design cable routes or corridors is useful for both sides as it raises awareness of each other’s needs. Efforts can be made to design cable routes in such a way that trawling is restricted as little as possible. Improving communication between cable companies and fishermen is key. Cable companies can engage in distributing charts or booklets to disseminate knowledge about cable position and potential dangers. The other way around, fishermen can communicate to companies where the most heavily fished areas are, so that these areas can be avoided when cable routes are planned. In the Netherlands, it is ensured during the planning phase that no cables or pipelines can be installed in anchoring locations, and that they should cross waterways in the shortest and straightest possible way, to avoid disrupting other activities such as fishing [24]. The institutionalising of cable / fishing committees within the MSP allows it to go further than informal dialogue and supports better management of sea space. More generally, the design and construction phases of the project are especially relevant for stakeholder dialogue and mutual dissemination of knowledge to prevent accidents. Choices for the most suitable implementation locations must be defined upstream when defining the project to reduce conflicts and increase compatibility with fishing activity. The early dialogue between the two parties is the prerequisite for the operating phase to go smoothly.
Considering the risks that we detailed in the ”related challenges” section, countries can develop targeted legislation that obliges cable and pipeline owners to use burial methods most suited to the location. Such methods include armoring or rock dumping where seabed substrates are unsuitable for burying cables and pipelines, to secure and make cables and pipelines safe. In Germany for example, legislation requires a minimum burial depth of 1,5 m. This depth must be increased if the cable is located in a heavily fished zone [25]. Moreover, if the cable is located in a zone known for rough seas or dense traffic, this depth must also be increased in case the vessel has to undertake anchor maneuvers in emergency. This is the case for example in the German bright (and more specifically in the Terschelling area), where the traffic Separation Scheme (TSS), used to safely manage the dense traffic, prescribes a burial depth of 3 m below the seabed [26].
The increased use of computer software linked to positioning systems such as GPS represents an opportunity to inform fishermen about cables in their surroundings but also to provide warnings if the vessel gets too close to the cable route. For example, Iceland uses a system where the cable coordinates are sent electronically to all surrounding local fishing vessels [27].
- References
DISCLAIMER: This page is based on the previous existing section “MSP Sectors and Conflicts” presented on the European MSP Platform, and where you can find the related fiche here.
Other references:
[4] https://www.pnas.org/doi/10.1073/pnas.1820344116
[11] https://www.iscpc.org/documents/?id=142
[13] https://www.bbc.com/news/world-europe-jersey-38141230
[14] https://www.barrons.com/news/finland-finds-anchor-that-likely-damaged-gas-pipeline-294395c0
Existing co-existence and multi-use initiatives
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